Chicago Commute Map updated with 2013 Census data

December 15, 2014 at 7:20 pm

The How Chicago Commutes map I created earlier this year has been updated with 2013 American Community Survey 5-year estimate data from the US Census.

I merely updated the information instead of creating links to compare the 2013 data with the 2012 data (from the original map). The information box that appears upon hovering over/clicking on a tract does not change to reflect the year selected, and only displays the 2013 data. Once I figure out a fix for this it will be easier to incorporate multiple years. Regardless, the data did not change much, and much of the ACS data has such a high margin of error that year over year changes may not be useful unless they are dramatic (i.e., at least a 10% change).

There are no big surprises with the new data; much is the same. People living at the edges of the city drive to work more often than people who live in denser neighbourhoods near transit, people who live downtown are more likely to walk to work, and so on. The bicycle commuting numbers are harder to interpret (the margins of error are also larger). Also note that the ACS only takes into account the longest commute mode: if a commute is multi-modal, e.g. you bike 5 minutes to a train you take for 30 minutes, only your train ride is counted.

And of course, there are still a lot of households (entire family units) that do not own a car, and whose transportation needs be taken into account by planners:

Capture d’écran 2014-12-15 à 17.16


(So you can stop building 500-space parking garages for north side housing developments, for example).

Due to some bugs with TileMill, which is used to stylize the census tracts, I had to explicitly state each number to format. It took a while, but the upside was the chance to see this progression:

Capture d’écran 2014-12-15 à 15.31.43Capture d’écran 2014-12-15 à 15.32.28 Capture d’écran 2014-12-15 à 15.32.50


This shows the progression of tracts where more than 50%, 70%, then 80% of workers are driving alone to work. I like how closely it matches other maps of Chicago, like this one from Daniel Kay Hertz that shows where it’s illegal to build anything other than single-family homes (thanks, zoning):

Map: Daniel Kay Hertz.

When you have lower density (i.e. single family homes) and less transit accessibility, people are probably going to drive to work more. Older, pre-war (i.e. pre-car) neighbourhoods have more transit commuters. But that could be just one of a few possible relationships, like: do the people living in lower density areas, which are closer to the city’s edge, work outside the city and not in the centre, which is more transit accessible? Are these people living somewhat close to transit but find the walk across a freeway bridge to access it unpleasant (think of the blue line)? There are a lot of assumptions that can be made by comparing data like this.

Have fun taking a look at the updated map!